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Resonant interactions between cometary ions and low frequency electromagnetic wavesThe conditions for resonant wave amplification in a plasma with a ring-beam distribution which is intended to model pick-up ions in a cometary environment are investigated. The inclination between the interplanetary field and the solar wind is found to play a crucial role in governing both the resonant frequency and the growth rate of any unstable mode. It is suggested that the low-frequency MHD mode should experience the most rapid amplification for intermediate inclination. In the frame of the solar wind, such waves should propagate along the field in the direction upstream toward the sun with a phase speed lower than the beaming velocity of the pick-up ions. This mechanism may account for the presence of the interior MHD waves noted by satellites over a region surrounding comets Giacobini-Zinner and Halley.
Document ID
19880037032
Document Type
Reprint (Version printed in journal)
Authors
Thorne, Richard M. (NERC British Antarctic Survey, Cambridge, United Kingdom)
Tsurutani, Bruce T. (California Institute of Technology Jet Propulsion Laboratory, Pasadena, United States)
Date Acquired
August 13, 2013
Publication Date
December 1, 1987
Publication Information
Publication: Planetary and Space Science
Volume: 35
ISSN: 0032-0633
Subject Category
ASTROPHYSICS
Funding Number(s)
CONTRACT_GRANT: NSF ATM-84-08270
CONTRACT_GRANT: NSF ATM-87-18108
Distribution Limits
Public
Copyright
Other